Apparatus for recording and reproducing sound



March 16, 1943.

C. WlCKLIFFE APPARATUS FOR RECORDING AND REPRODUCING SOUND Filed May 24, 1940 To sou'Rct:

20oF PovvER k Patented Mar. 16, 1943 UNITED STATES PATENT OFFICE APPARATUS FOR RECORDING AND REPRODUCING SOUND (Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 O. G. 757) 3 Claims.

This invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates generally to a process and an apparatus for recording and reproducing sound, but more particularly to the production of hard. smooth sound tracks on motion picture film.

One object of the invention is to provide a simple and inexpensive method and apparatus for producing a smooth surfaced sound track of music, explanatory notes, or sound effects upon a moving picture film, so that the sounds can be reproduced with the projection of the picture thereon with a high degree of fidelity.

Another object of the invention is to provide a process and apparatus for producing a sound track on motion picture film, and to simultaneously coat the surface of said track so as to furnish it with a hard smooth facing, and thus eliminate extraneous noises caused by the scratching of a reproducing needle.

Another object of the invention is to provide a method and means for renewing the worn surface of a sound track already cut, and to thus prevent the reproducing needle from cutting into the surface of the acetate on used films.

With these and other objects in View, the invention consists in certain novel details of con struction, combination and arrangement of parts which will further be described and claimed.

Referring to the drawing in which like parts are indicated by similar reference characters: v

Fig. 1 is a diagrammatic view showing the operation of the sound recording and reproducing device in connection with a projector;

Fig. 2 is a side elevation of the sound recording and reproducing device showing the relative arrangement of the fihn base, the tone arm with recording reproducing head and the moistening tube;

3 is a top plan view of the apparatus shown in Fig. 1;

Fig. 4 is a diagrammatic view showing hook-up used when reproducing sound;

The reproduction of sound :by cutting a sound track upon a record is usually accompanied by extraneous noises caused by the roughness of the surface of the track, which increases with use since the passage of th reproducing needle through the groove causes wear which further roughens the already unsmooth surface.

The underlying principle of the instant invention is to provide a smooth surface within the groove of the sound track by applying a liquid which will dissolve a portion of the materialon the surface of the track, so that this material will flow over the surface and into the crevices to thus eliminate projections and depressions and provide a smooth groove of constant depth through which the reproducing needle may pass without encountering obstructions which deflect it from its path, and thus cause surface noises.

In the instant invention the smoothing of the track is accomplished by painting it with acetone or any other substance which will dissolve a small portion of the base beneath the emulsive surface of the film. The solution thus formed hardens within the groove of the track and thus provides the latter with a smooth hard facing which is more resistant to the cutting effect of th repro ducing needle.

Briefly stated, the recording and reproducing device comprises an apparatus through which a moving picture film is passed for the purpose of cutting a sound track thereon, and for so treating said track, so as to form a smooth hard surface within its groove. The device can also be used for sound reproduction purposes, or for re newing the surface of worn sound tracks to eliminate extraneous noises.

The recording and reproducing device shown in detail in Figs. 2 and 3, comprises a base as indicated by the numeral [0, on which is mounted an arcuately curved film track I I, idler rollers l2 and I3 rotatably mounted in bracket bearings l4, l4

of the base opposite said film track. The arcuate track and the idler rollers provide a path for the film as it moves under the recording or reproducing needle, as will be described.

The recorder and reproducer head '20, which is preferably of the electric type to permit audioamplification, is mounted upon a tone arm 2|, which is rigidly attached to a shaft 22. The shaft 22, which is supported by bracket bearings 23 and 24 is threaded at one end and fitted with an adjusting bushing or nut 25 to provide for lateral adjustment of the shaft 22. As will be noted from Fig. 2, one end of the shaft is rotatably mounted Within the bracket bearing 24, and the other end of the shaft is threadably engaged by the nut 25, which isrotatably mounted within the bearing 23. The nut 25 consists of an internally threaded tubular portion 26 having collars 21 and 28 and an adjusting disk 29 by which it may be rotated within the bearing 23 toimpart a lateral movement to the tone arm 2| to which the recorder andreproducerZfl is attached.

The tone arm is fitted with a slidably adjustable weight 39, which may be locked in any position along the arm by means of the set screw 3| to regulate the pressure exerted by the needle or stylus 32 of the recorder and reproducer upon the film 43.

A tubular reservoir 33 which is tapered a'djacent its lower end into a tube 34 of smaller Fig. 1, which illustrates the manner in which the recording and reproducing device is utilized, the numeral 39 indicates a motion picture projector which is mounted upon a table 40; 4| is the recording and reproducing device which is mounted on a suitable support '42 attached to the table 4! adjacent the projector. Film 43 from the payout or idler reel 44 is passed over the idler roller I'I, under idler rollers I6 and I3, over the arcuate track I I and under idler roller I2 to the constant speed feed sprocket 45 of the projector. .From the feed sprocket 45 the film forms a loop which passes through the gate 46 and over the constant speed sprocket 4'! to the winding reel 48.

As the film which is composed of an acetate base coated on one side'by an emulsion,passes over the arcuate track I I, it is engaged on its emulsion coating by the point of the recording stylus 32, which cuts a sound track therein in accordance with the sound delivered to a micro.- phone G9, which is in electrical connection with the recorder and reproducer head 20, through the conductors 59, 5| and 53, which complete a circuit supplied by a source of power 52.

Either simultaneously with the cutting of the track or after the track is entirely cut, a solvent such as acetone or any other suitable solvent contained within the reservoir 33 is allowed to moisten the track as the film is passed beneath the Wick 32. acetate base of the film at the bottom of the track, as the wick wipes it smooth, and as the solution hardens rapidly it forms a hard smooth path for the passage of the reproducing needle, thus eliminating the harsh grating sound so common to phonographic reproduction.

Since the acetone or fiuid used in the process is one that will not affect the emulsion but will dissolve the acetate or nitrate base upon which the emulsion is coated, the track or path cut in base only where it has been exposed by the path out in the emulsion and thereby etching in the said base a track which corresponds or registers with that cut in the emulsion.

In forming the sound track the cutting of the acetate base by the recording needle is to be avoided and therefore the counterweight 30 is provided so as to limit the depth of the cut to the thickness of the emulsive coating of the film.

When reproducing, the apparatus is used as an electric pick-up, as shown diagrammatically in Fig. 4. The head 20 is connected through an amplifying unit 54 to a loud speaker 55. a

A bracket 55 is mounted on the base It] to function as a support for the tone arm 2|, when theneedle or stylus 32 is removed from the reproducer and recorder head 20. By removing the needle or stylus 32 the device can be used for smoothing the surface of sound tracks.

In the drawings a reservoir provided with a wick is shown for applying the solvent to the sound track. The solvent could also be applied means.

The moistening solvent softens the Although in the foregoing certain elements have been described as best adapted to perform the functions allotted to them, nevertheless it is to be understood that certain changes may be resorted to without departing from the spirit and scope of the invention as disclosed in the appended claims.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A device for forming sound tracks on motion picture film comprising, a base, an arcuately shaped film track mounted on said base, adapted for the movement of film thereon, a laterally adjustable, arcuately movable tone arm mounted on said base, a recording and reproducing head positioned at the extremity of said tone arm, so that its reproducing and recording stylus con tacts said film, an L-shaped bracket supporting a tubular solvent reservoir, provided with a downwardly projecting wick, said bracket adapted to be mounted at points along saidtone arm so as to vary the spacing between said wick and said stylus. e

2. A device for forming sound tracks on motion picture film comprising, a base, an arcuately shaped film track mounted on said base, adapted for the movement of film thereon, brackets attached to said base. a shaft mounted for lateral adjustment within said brackets, and a tone arm mounted on said shaft so as to permit arcuate movement thereof, and lateral movement with the adjustment of said shaft within said brackets, a recording and reproducing head positioned at the extremity of said tone arm, so that its reproducing and recording stylus contacts said film, and an L-shaped bracket supporting a solvent reservoir, provided with a restricted tubular portion adapted to retain a downwardly projecting Wick for moistening said sound track, said bracket being adapted to be mounted at points along said tone arm so as to vary the spacing between the contact points of the stylus and said wick along the sound track.

3. A device for forming a plurality of longitudinally arranged sound tracks on motion picture film comprising, a base, an arcuately shaped fihn track mounted on said base forming a bearing surface within a film path, bearing brackets attached to said base on either side of the film path, an internally threaded adjusting bushing rotatably mounted within one of said brackets,.a partially threaded shaft threadedly engaged by said adjusting bushing of one bracket and slidably mounted within a bearing in the other bracket whereby lateral movement of said shaft may be effected by the rotating movement of said adjusting bushing, a tone arm mounted on said shaft so as to permit arcuate movement thereof, and lateral movement with the adjustment of said shaft, a recording and reproducing head p0- sitioned at the extremity of said tone arm, so that its reproducing and recording stylus contacts said film, and an L-shaped bracket supporting a solvent reservoir, provided with a restricted tubular portion adapted to retain a wick in a downwardly projecting position for moistening said sound track, said bracket being adapted to be mounted at points along said tone arm so as to vary the spacing between the contact points of tlile stylus and said wick along the sound rac CHARLES A. WICKLIFFE. 

